fb13a28b0f
Add comments describing struct snapshot_handle and its members, change the confusing name of its member 'page' to 'cur'. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
165 lines
5.5 KiB
C
165 lines
5.5 KiB
C
#include <linux/suspend.h>
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#include <linux/utsname.h>
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struct swsusp_info {
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struct new_utsname uts;
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u32 version_code;
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unsigned long num_physpages;
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int cpus;
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unsigned long image_pages;
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unsigned long pages;
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unsigned long size;
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} __attribute__((aligned(PAGE_SIZE)));
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#ifdef CONFIG_SOFTWARE_SUSPEND
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extern int pm_suspend_disk(void);
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#else
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static inline int pm_suspend_disk(void)
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{
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return -EPERM;
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}
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#endif
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extern struct semaphore pm_sem;
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#define power_attr(_name) \
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static struct subsys_attribute _name##_attr = { \
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.attr = { \
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.name = __stringify(_name), \
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.mode = 0644, \
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}, \
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.show = _name##_show, \
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.store = _name##_store, \
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}
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extern struct subsystem power_subsys;
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/* References to section boundaries */
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extern const void __nosave_begin, __nosave_end;
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extern struct pbe *pagedir_nosave;
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/* Preferred image size in bytes (default 500 MB) */
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extern unsigned long image_size;
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extern int in_suspend;
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extern dev_t swsusp_resume_device;
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extern asmlinkage int swsusp_arch_suspend(void);
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extern asmlinkage int swsusp_arch_resume(void);
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extern unsigned int count_data_pages(void);
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/**
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* Auxiliary structure used for reading the snapshot image data and
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* metadata from and writing them to the list of page backup entries
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* (PBEs) which is the main data structure of swsusp.
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*
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* Using struct snapshot_handle we can transfer the image, including its
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* metadata, as a continuous sequence of bytes with the help of
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* snapshot_read_next() and snapshot_write_next().
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*
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* The code that writes the image to a storage or transfers it to
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* the user land is required to use snapshot_read_next() for this
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* purpose and it should not make any assumptions regarding the internal
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* structure of the image. Similarly, the code that reads the image from
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* a storage or transfers it from the user land is required to use
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* snapshot_write_next().
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*
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* This may allow us to change the internal structure of the image
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* in the future with considerably less effort.
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*/
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struct snapshot_handle {
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loff_t offset; /* number of the last byte ready for reading
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* or writing in the sequence
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*/
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unsigned int cur; /* number of the block of PAGE_SIZE bytes the
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* next operation will refer to (ie. current)
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*/
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unsigned int cur_offset; /* offset with respect to the current
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* block (for the next operation)
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*/
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unsigned int prev; /* number of the block of PAGE_SIZE bytes that
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* was the current one previously
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*/
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struct pbe *pbe; /* PBE that corresponds to 'buffer' */
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struct pbe *last_pbe; /* When the image is restored (eg. read
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* from disk) we can store some image
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* data directly in the page frames
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* in which they were before suspend.
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* In such a case the PBEs that
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* correspond to them will be unused.
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* This is the last PBE, so far, that
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* does not correspond to such data.
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*/
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void *buffer; /* address of the block to read from
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* or write to
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*/
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unsigned int buf_offset; /* location to read from or write to,
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* given as a displacement from 'buffer'
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*/
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int sync_read; /* Set to one to notify the caller of
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* snapshot_write_next() that it may
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* need to call wait_on_bio_chain()
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*/
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};
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/* This macro returns the address from/to which the caller of
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* snapshot_read_next()/snapshot_write_next() is allowed to
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* read/write data after the function returns
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*/
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#define data_of(handle) ((handle).buffer + (handle).buf_offset)
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extern int snapshot_read_next(struct snapshot_handle *handle, size_t count);
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extern int snapshot_write_next(struct snapshot_handle *handle, size_t count);
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int snapshot_image_loaded(struct snapshot_handle *handle);
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#define SNAPSHOT_IOC_MAGIC '3'
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#define SNAPSHOT_FREEZE _IO(SNAPSHOT_IOC_MAGIC, 1)
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#define SNAPSHOT_UNFREEZE _IO(SNAPSHOT_IOC_MAGIC, 2)
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#define SNAPSHOT_ATOMIC_SNAPSHOT _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
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#define SNAPSHOT_ATOMIC_RESTORE _IO(SNAPSHOT_IOC_MAGIC, 4)
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#define SNAPSHOT_FREE _IO(SNAPSHOT_IOC_MAGIC, 5)
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#define SNAPSHOT_SET_IMAGE_SIZE _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
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#define SNAPSHOT_AVAIL_SWAP _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
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#define SNAPSHOT_GET_SWAP_PAGE _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
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#define SNAPSHOT_FREE_SWAP_PAGES _IO(SNAPSHOT_IOC_MAGIC, 9)
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#define SNAPSHOT_SET_SWAP_FILE _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
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#define SNAPSHOT_S2RAM _IO(SNAPSHOT_IOC_MAGIC, 11)
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#define SNAPSHOT_IOC_MAXNR 11
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/**
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* The bitmap is used for tracing allocated swap pages
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*
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* The entire bitmap consists of a number of bitmap_page
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* structures linked with the help of the .next member.
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* Thus each page can be allocated individually, so we only
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* need to make 0-order memory allocations to create
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* the bitmap.
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*/
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#define BITMAP_PAGE_SIZE (PAGE_SIZE - sizeof(void *))
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#define BITMAP_PAGE_CHUNKS (BITMAP_PAGE_SIZE / sizeof(long))
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#define BITS_PER_CHUNK (sizeof(long) * 8)
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#define BITMAP_PAGE_BITS (BITMAP_PAGE_CHUNKS * BITS_PER_CHUNK)
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struct bitmap_page {
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unsigned long chunks[BITMAP_PAGE_CHUNKS];
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struct bitmap_page *next;
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};
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extern void free_bitmap(struct bitmap_page *bitmap);
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extern struct bitmap_page *alloc_bitmap(unsigned int nr_bits);
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extern unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap);
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extern void free_all_swap_pages(int swap, struct bitmap_page *bitmap);
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extern int swsusp_check(void);
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extern int swsusp_shrink_memory(void);
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extern void swsusp_free(void);
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extern int swsusp_suspend(void);
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extern int swsusp_resume(void);
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extern int swsusp_read(void);
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extern int swsusp_write(void);
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extern void swsusp_close(void);
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extern int suspend_enter(suspend_state_t state);
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